Marker delivery device with releasable plug

ABSTRACT

The invention is directed to marker delivery devices and methods of using such devices. The delivery devices embodying features of the invention include a delivery cannula with a discharge opening and a releasable plug disposed in the inner lumen of the delivery cannula so as to at least partially occlude the discharge opening. The releasable plug prevents ingress of tissue, body fluids and the like into the bore of the tube, and prevents the premature discharge of any markers proximal to the releasable plug from passing through the discharge opening before the distal end of the cannula is properly positioned at a desired location within a patient&#39;s body. The releasable plug preferably has an MRI detectable element. Preferably, at least one remotely detectable marker mass is provided in the inner lumen of the cannula proximal to the releasable plug.

RELATED APPLICATIONS

[0001] This application is a continuation-in-part of application Ser.No. 10/444,770, filed on May 23, 2003 which is incorporated herein byreference in its entirety and from which priority is claimed.

FIELD OF THE INVENTION

[0002] The invention is generally directed to devices and methods forthe delivery of remotely detectable markers to a desired location withina patient's body. In particular, the invention is directed to devices,and methods configured to retain a remotely detectable marker within adelivery device before delivery to a desired intracorporeal location.

BACKGROUND OF THE INVENTION

[0003] In diagnosing and treating certain medical conditions, it isoften desirable to mark a suspicious body site for the subsequent takingof a biopsy specimen, for delivery of medicine, radiation, or othertreatment, for the relocation of a site from which a biopsy specimen wastaken, or at which some other procedure was performed. As is known,obtaining a tissue sample by biopsy and the subsequent examination aretypically employed in the diagnosis of cancers and other malignanttumors, or to confirm that a suspected lesion or tumor is not malignant.The information obtained from these diagnostic tests and/or examinationsis frequently used to devise a therapeutic plan for the appropriatesurgical procedure or other course of treatment.

[0004] In many instances, the suspicious tissue to be sampled is locatedin a subcutaneous site, such as inside a human breast. To minimizesurgical intrusion into a patient's body, it is often desirable toinsert a small instrument, such as a biopsy needle, into the body forextracting the biopsy specimen while imaging the procedure usingfluoroscopy, ultrasonic imaging, x-rays, magnetic resonance imaging(MRI) or any other suitable form of imaging technique. Examination oftissue samples taken by biopsy is of particular significance in thediagnosis and treatment of breast cancer. In the ensuing discussion, thebiopsy and treatment site described will generally be the human breast,although the invention is suitable for marking biopsy sites in otherparts of the human and other mammalian body as well.

[0005] Periodic physical examination of the breasts and mammography areimportant for early detection of potentially cancerous lesions. Inmammography, the breast is compressed between two plates whilespecialized x-ray images are taken. If an abnormal mass in the breast isfound by physical examination or mammography, ultrasound may be used todetermine whether the mass is a solid tumor or a fluid-filled cyst.Solid masses are usually subjected to some type of tissue biopsy todetermine if the mass is cancerous.

[0006] If a solid mass or lesion is large enough to be palpable, atissue specimen can be removed from the mass by a variety of techniques,including but not limited to open surgical biopsy, a technique known asFine Needle Aspiration Biopsy (FNAB) and instruments characterized as“vacuum assisted large core biopsy devices”.

[0007] If a solid mass of the breast is small and non-palpable (e.g.,the type typically discovered through mammography), a vacuum assistedlarge core biopsy procedure is usually used. In performing astereotactic biopsy of a breast, the patient lies on a special biopsytable with her breast compressed between the plates of a mammographyapparatus and two separate x-rays or digital video views are taken fromtwo different points of view. A computer calculates the exact positionof the lesion as well as depth of the lesion within the breast.Thereafter, a mechanical stereotactic apparatus is programmed with thecoordinates and depth information calculated by the computer, and suchapparatus is used to precisely advance the biopsy needle into the smalllesion. The stereotactic technique may be used to obtain histologicspecimens. Usually at least five separate biopsy specimens are obtainedfrom locations around the small lesion as well as one from the center ofthe lesion.

[0008] The available treatment options for cancerous lesions of thebreast include various degrees of mastectomy or lumpectomy, radiationtherapy, chemotherapy and combinations of these treatments. However,radiographically visible tissue features, originally observed in amammogram, may be removed, altered or obscured by the biopsy procedure,and may heal or otherwise become altered following the biopsy. In orderfor the surgeon or radiation oncologist to direct surgical or radiationtreatment to the precise location of the breast lesion several days orweeks after the biopsy procedure was performed, it is desirable that abiopsy site marker be placed in the patient's body to serve as alandmark for subsequent location of the lesion site. A biopsy sitemarker may be a permanent marker (e.g., a metal marker visible underx-ray examination), or a temporary marker (e.g., a bioresorbable markerdetectable with ultrasound). While current radiographic type markers maypersist at the biopsy site, an additional mammography generally must beperformed at the time of follow up treatment or surgery in order tolocate the site of the previous surgery or biopsy. In addition, once thesite of the previous procedure is located using mammography, the sitemust usually be marked with a location wire which has a hook on the endwhich is advanced into site of the previous procedure. The hook is meantto fix the tip of the location wire with respect to the site of theprevious procedure so that the patient can then be removed from theconfinement of the mammography apparatus and the follow-up procedureperformed. However, as the patient is removed from the mammographyapparatus, or otherwise transported the position of the location wirecan change or shift in relation to the site of the previous procedure.This, in turn, can result in follow-up treatments being misdirected toan undesired portion of the patient's tissue.

[0009] As an alternative or adjunct to radiographic imaging, ultrasonicimaging (herein abbreviated as “USI”) or visualization techniques can beused to image the tissue of interest at the site of interest during asurgical or biopsy procedure or follow-up procedure. USI is capable ofproviding precise location and imaging of suspicious tissue, surroundingtissue and biopsy instruments within the patient's body during aprocedure. Such imaging facilitates accurate and controllable removal orsampling of the suspicious tissue so as to minimize trauma tosurrounding healthy tissue.

[0010] For example, during a breast biopsy procedure, the biopsy deviceis often imaged with USI while the device is being inserted into thepatient's breast and activated to remove a sample of suspicious breasttissue. As USI is often used to image tissue during follow-up treatment,it may be desirable to have a marker, similar to the radiographicmarkers discussed above, which can be placed in a patient's body at thesite of a surgical procedure and which are visible using USI. Such amarker enables a follow-up procedure to be performed without the needfor traditional radiographic mammography imaging which, as discussedabove, can be subject to inaccuracies as a result of shifting of thelocation wire as well as being tedious and uncomfortable for thepatient.

[0011] Placement of a marker or multiple markers at a location within apatient's body requires delivery devices capable of holding markerswithin the device until the device is properly situated within a breastor other body location. Accordingly, devices and methods for retainingmarkers within a marker delivery device while allowing their expulsionfrom the devices at desired intracorporeal locations are desired.

SUMMARY OF THE INVENTION

[0012] The invention is generally directed to the delivery of one ormore markers to an intracorporeal site within a patient's body. A markerdelivery device embodying features of the invention include a deliverytube or cannula having an inner lumen leading to a discharge opening andhaving a releasable plug which is disposed at least in part within theinner lumen and which at least partially occludes the discharge openingin the distal end of the delivery tube.

[0013] The releasable plug is configured to occlude or block off thedischarge opening of the delivery cannula or the inner lumen leadingthereto to prevent tissue and fluid from entering the inner lumenthrough the discharge opening during delivery and to hold in any othermarkers within the inner lumen proximal to the releasable plug duringhandling and delivery. In one embodiment having features of theinvention, the delivery device has a releasable plug with a remotelydetectable marker element incorporated therein. Preferably, the markerelement incorporated into the releasable plug is non-magnetic andremotely detectable by magnetic resonance imaging.

[0014] In yet another embodiment having features of the invention, thedelivery device has a releasable plug and has at least one short term,remotely detectable marker mass in the inner lumen or at least onefibrous marker in the inner lumen proximal to the releasable plug.Preferably, at least one short term marker and at least one fibrousmarker are disposed within the inner lumen of the delivery cannula.

[0015] The releasable plug may be secured within the inner lumen by avariety of means, but It is preferred to press fit the plug into thedistal portion of the inner lumen so as to occlude the dischargeopening. However, the plug may alternatively be mechanically oradhesively secured within the distal portion of the inner lumen. Forfurther plug details see co-pending application Ser. No. 10/174,401,filed on Jun. 17, 2002, entitled Plugged Tip Delivery Tube For MarkerPlacement which is incorporated herein in its entirety by reference.However, the releasable plug should be configured to be easily pushedout of the discharge opening of the delivery cannula, even if thereleasable plug has swollen due to contact with a water based fluid. Asdescribed above, the releasable plug preferably has a non-magnetic, MRIdetectable element which does not interfere with the subsequent imagingof adjacent tissue. The MRI detectable element is about 0.5 to about 5mm in maximum dimension, preferably about 1 to about 3 mm. Suitablenon-magnetic, MRI detectable materials include titanium, platinum, gold,iridium, tantalum, tungsten, silver, rhodium and the like.

[0016] The releasable plug is formed of a biocompatible, preferablybioabsorbable material such as oxidized regenerated cellulose,polyethylene glycol, polylactic acid, polyglycolic acid, polycaproicacid, and copolymers, polymer alloys, polymer blends, and combinationsthereof. Preferable materials are oxidized regenerated cellulose andpolymers of polyethylene glycol with molecular weights of about 5000 toabout 120,000 Daltons. The releasable plug should be formed of a waterswellable material, so that it swells upon contact with water basedfluids (e.g. body fluids) to further occlude or otherwise seal thedischarge opening of the delivery cannula and thereby prevent prematurecontact of body fluids with any markers within the inner lumen proximalto the releasable plug. The plug may also be formed of fibrous materialsand be in the form of a fibrous marker described below.

[0017] The short term markers disposed within the inner lumen of thedelivery cannula proximal to the releasable plug should be remotelydetectable for at least two weeks, preferably at least up to six weeks,but not longer than about one year, preferably not more than about sixmonths, so as to not interfere with subsequent imaging of the targetsite. The short term markers are preferably formed of bioabsorbablepolymeric materials such as polymers of lactic acid, glycolic acid andcaprolactones and copolymers and blends thereof. Other suitablematerials include those described in co-pending application Ser. No.09/717,909, filed Nov. 20, 2000 and co-pending application Ser. No.10/124,757, filed on Jun. 17, 2002, both of which are incorporated byreference in their entireties. The plug and the short term markers maybe formed of the same or similar material. The releasable plug may alsobe formed of fibrous material and be in the form of the fibrous markersdescribed below.

[0018] The fibrous marker should be slidably disposed within the innerlumen of the delivery cannula, preferably proximal to at least one shortterm marker so that upon discharge from the cannula into a target site,the fibrous marker will block the accessing passageway and prevent lossof marker material therethrough. A suitable material for forming thefibrous marker is a felt and/or fiber material formed of oxidizedregenerated cellulose which has an in vivo lifetime of a few hours up toabout 6 weeks, typically about 3 days to about 4 weeks. However, thefibrous marker may be formed of a bioabsorbable polymer such aspolylactic acid or polyglycolic acid, a co-polymer of polylactic acidand polyglycolic acid, polycaprolactone, collagen and mixtures thereof,including mixtures with oxidized regenerated cellulose. Suitableoxidized, regenerated cellulose includes SURGICEL™ from the EthiconDivision of Johnson & Johnson or other suitable oxidized regeneratedcellulose which are naturally hemostatic. Alternatively, a hemostaticagent such as collagen, gelatin or polysaccharides may be incorporatedinto the fibrous material to provide the hemostasis upon contact withblood. A wide variety of other hemostatic agents may be incorporatedinto the marker. The thrombus formed by the hemostasis is formed veryquickly to fill the cavity at the biopsy site and at least temporarilyhold the plug and any other markers in position within the cavity.Anesthetic agents to control post procedure pain, chemotherapeuticagents to kill any residual neoplastic tissue and coloring agents (e.g.carbon black and methylene blue) for visual location of the biopsy site,may also be incorporated into the fibrous marker.

[0019] The fibrous material is formed into an elongated member, e.g. byrolling or folding, and bound in a compressed condition to providesufficient column strength to facilitate introduction into and dischargefrom a tubular delivery device. Suitable binding agents for holding thefibrous marker in a compressed condition are water soluble polymers suchas polyvinyl alcohol, polyethylene glycol, polyvinyl pyrollidone. One ormore radiographically detectable marker elements are provided with atleast one of the fibrous markers, preferably centrally located on theelongated marker to ensure that the radiographically detectable elementis disposed at a more or less central location within the target siterather than at a site margin.

[0020] The releasable plug, the short term markers and the fibrousmarkers may include a variety of therapeutic or diagnostic materialssuch as hemostatic agents, anesthetic agents, coloring agents,antibiotics, antifungal agents, antiviral agents, chemotherapeuticagents, radioactive agents and the like.

[0021] The delivery device preferably has a plunger slidably disposedwithin the inner lumen of the delivery cannula which is movable from aninitial position accommodating the releasable plug and any markersproximal to the plug within the tube, to a delivery position to push theplug and any desired number of markers out of the discharge opening inthe distal end of the cannula into the target tissue site.

[0022] Upon being discharged into the intracorporeal target site, themarkers at least partially fill the site to enable short term detectionby remote imaging and preferably long term detection by remote imagingwithout interfering with imaging of tissue adjacent to the site. Themarkers may swell on contact with body fluid, e.g. blood so as tofurther fill the biopsy cavity. The fibrous marker partially fills thecavity at the target site, positioning the radiopaque marker elementwithin the interior of the target cavity.

[0023] The marker mass proximal to the releasable plug may be in theform of ultrasound-detectable, bio-resorbable finely-divided particulatematerial (such as a powder or granulated material), in which many of theparticles have internal cavities. Such particulate materials preferablyhave particle sizes less than about 2000 microns, and typically betweenabout 20 microns and about 2000 microns. For optimum delivery and markerresolution, the particulate should have a particulate size of about 20microns to about 1500 microns, preferably about 500 microns to about 800microns. The ultrasound-detectable, bio-resorbable particulate materialsmay be formed of polymeric materials such as polylactic acid,polyglycolic acid, polycaprolactone, and combinations of these polymersand the particulate may be bound by suitable binding agents such asgelatin, polyethylene glycol, polyvinyl alcohol, glycerin,polysaccharides, other hydrophilic materials, and combinations of these.Suitable gelatins include bovine collagen, porcine collagen, ovinecollagen, equine collagen, synthetic collagen, agar, synthetic gelatin,and combinations of these. Further details of the particulate markermaterial and the delivery thereof can be found in co-pending applicationSer. No. 10/124,757, which has been incorporated herein. Polysaccharideparticulate or powder may be included with the other particulatematerials as a hemostatic agent.

[0024] The delivery tube of the device may be configured to fit within aguide cannula, such as a Mammotome® or SenoCor 360™ biopsy cannula or acoaxial needle guide.

[0025] The ultrasound-detectable biopsy site markers of the presentinvention provide several advantages. A biopsy cavity with markermaterial having features of the present invention provides a largeUSI-bright mass, making it much easier, for example, to distinguish theultrasound signal of the marker from signals arising naturally fromwithin a breast. The marker materials produce bright ultrasound echosignals from one portion of the filled region, which contrasts with thedark ultrasound shadow region immediately behind the bright ultrasoundecho region. The strength of the reflected signal, and the contrast withthe shadow region, make the marked site readily detectable. Such readydetectability allows, for example, less-experienced physicians toperform the identification by USI and the subsequent surgical resectionwithout the need for an interventional radiologist to identify and markthe biopsy cavity. When a MRI marker element is incorporated into thereleasable plug or the short term markers, the target site in which themarkers are deployed may be subsequently detected by ultrasound,magnetic resonance and X-ray without interfering with imaging adjacenttissue at a later date.

[0026] The invention provides the advantages of securely retainingmarkers within a marker delivery device, improving accuracy and avoidingerrors in placement of markers at desired locations within a patient'sbody, preventing ingress of tissue into the distal tip of the devicewhen it is advanced through tissue, and guiding the device by use of animaging device including ultrasound, X-ray and magnetic resonance baseddevices. These and other advantages of the invention will become moreapparent from the following description when taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1A is a partly cut-away perspective view of a marker deliveryassembly embodying features of the invention.

[0028]FIG. 1B is a transverse cross-sectional view of the markerdelivery assembly of FIG. 1A taken at line 1B-1B.

[0029]FIG. 1C is a transverse cross-sectional view of the markerdelivery assembly of FIG. 1A taken at line 1C-1C.

[0030]FIG. 2 is an end perspective view of a fibrous marker with a coremember suitable for use with a marker delivery system embodying featuresof the invention.

[0031]FIG. 3 is an end perspective view of an alternative fibrous markerwithout a core member suitable for use with a marker delivery systemembodying features of the invention.

[0032]FIG. 4A-4F illustrates forming a fibrous marker with a core memberas depicted in FIG. 4.

[0033]FIG. 5 is a partially cut away, perspective view of a human breastfrom which a biopsy specimen has been removed, showing a markers beingdelivered to the biopsy site with the marker delivery assembly shown inFIG. 1A.

[0034]FIG. 6 is a partial cut-away view of a human breast shown in FIG.2 with the markers delivered into the biopsy site and the deliverydevice removed.

[0035]FIG. 7 is a longitudinal cross-sectional view of the distalportion of an alternative marker delivery device embodying features ofthe invention with a sharp, tissue penetrating distal tip.

[0036] FIGS. 8 is a longitudinal cross-sectional view of the distalportion of a marker delivery device embodying features of the inventionhaving particulate marker mass proximal to the releasable plug.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0037]FIGS. 1A-1C illustrate a marker delivery device 10 embodyingfeatures of the invention which includes a delivery tube or cannula 11with a bore 12, a distal portion 13, and a proximal portion 14 with ahandle 15. A releasable distal plug 16, several (five) short termmarkers 17, a pair of fibrous markers 18 and 19 and a proximal plug 20are shown disposed within the bore 12. A plunger 21 is slidably disposedwithin the tube bore 12, and is provided with a proximal end 22configured to allow an operator to press the plunger further into thebore 12 and push the releasable plug 16 and one or more of the othermarkers out of the discharge port or opening 23 in the distal end 24 ofdelivery tube 11. Cannula handle 15 allows an operator to hold thecannula steady while pressing plunger 21 to discharge the releasableplug 16 and markers 17 and 18.

[0038] Releasable plug 16 may substantially fill the discharge opening23, as shown in FIG. 1, or may occupy or block only a portion of thedischarge opening 23. The exposed face of plug 16 is preferably providedwith an inclined configuration to conform with the inclination of thedischarge opening 23.

[0039] Markers 17, 18 and 19 and proximal plug 20 are preferablyconfigured to slide readily within tube bore 12. Releasable plug 16 isconfigured to be tight enough, e.g. press fit, in the bore 12 to preventits inadvertent release which would allow premature discharge of markers17 and 18 from delivery tube 11 and undesirable contact with body fluid.But the plug 16 must be easily released when the plunger 21 is presseddeeper into the bore 12 of the delivery tube 11. An adhesive ormechanical element(s) may be used to hold the releasable plug 16 in aposition within the bore 12 to occlude the discharge opening 23.Suitable adhesives include polyurethane or polyacrylic based adhesives,polyhydroxymethacrylate base adhesives, fibrin glue (e.g., Tisseal™),collagen adhesive, or mixtures thereof. Suitable mechanical means forsecuring the releasable plug 16 are described in co-pending applicationSer. No. 10/174,401 which has been incorporated herein. The distal end24 of the delivery cannula 11 is provided with a ramp 25 which guidesthe discharged plug 16 and markers 17, 18 and 19 out of the side port 26into the target site. The distal tip 27 may be tapered for deliverythrough a guide tube as shown.

[0040] The delivery tube 11 may be provided with markings 28 which serveas visual landmarks to aid an operator in accurately placing the distalend 24 of the cannula 11 in a desired location within a patient“s bodyfor discharging the markers. The markings 24 also be radiopaque,ultrasound-reflective, or otherwise configured to be detectable byremote imaging devices and imaging methods.

[0041] Short term markers 17 are made at least in part with detectable,biocompatible materials. Suitable marker materials include bioresorbablepolymeric materials such as poly(esters), poly(hydroxy acids),poly(lactones), poly(amides), poly(ester-amides), poly(amino acids),poly(anhydrides), poly(ortho-esters), poly(carbonates),poly(phosphazines), poly(thioesters), poly(urethanes), poly(esterurethanes), polysaccharides, polylactic acid, polyglycolic acid,polycaproic acid, polybutyric acid, polyvaleric acid, and copolymers,polymer alloys, polymer blends, and combinations thereof. Preferablepolymeric materials are polymers of lactic acid, glycolic acid andcaprolactones. The short term markers 17 may also be formed at least inpart of gelatin. One or more of the short term markers 17 may include aremotely detectable preferably radiopaque element 28.

[0042] Releasable plug 16 is preferably formed at least in part ofoxidized regenerated cellulose or polyethylene glycol, but may be madefrom the same or similar bioabsorbable materials as marker 17. Thepolyethylene glycol quickly expands when contacting a water based fluidsuch as blood, which ensures that the releasable plug seals off thedischarge opening to prevent premature contact between body fluid (orother water based fluid) and the markers 17 and 18 within the bore 12.The polyethylene glycol should have a molecular weight of about 5000 toabout 20000 Daltons, preferably about 8000 to about 10000 Daltons in thefinal plug form. The releasable plug 16 preferably has a non-magneticelement 29 incorporated within the body of the releasable plug that isremotely detectable by magnetic resonance imaging (MRI). It may beformed of titanium, platinum, gold, iridium, tantalum, tungsten, silver,rhodium and the like. The MRI detectable element 29 should have amaximum dimension of about 0.5 to about 5 mm, preferably about 1 toabout 3 mm to be MRI detectable. Elements with dimensions greater thanabout 5 mm tend to interfere with the imaging of adjacent tissue.

[0043] Releasable plug 16 and markers 17 and 18 are configured for aslidable fit within the bore 15 of the delivery tube 11. The exterior ofthe delivery tube 11 is preferably configured to fit within a guidecannula sized to accept a Mammotome®, Tru-Cut®, or SenoCor® biopsydevice. Typically, plug 16 and markers 17 and 18 will have diametersdetermined by the size of a bore 15 and typically will be about 0.02inch (0.5 mm) to about 0.5 inch (12 mm), preferably about 0.04 inch (1mm) to about 0.3 inch (8 mm). Plug 16 may have slightly largertransverse dimensions to provide a tight fit. In addition, plugs 16 and19 and short term marker 17 will have a length of about 0.04 inch (1 mm)to about 0.8 inch (20 mm), preferably about 0.1 inch (2.5 mm) to about0.6 inch (15 mm).

[0044] Releasable plug 16, markers 17, 18 and 19 and plug 20 areconfigured for a slidable fit within the bore 15 of the delivery tube11. The exterior of the delivery tube 11 is preferably configured to fitwithin a guide cannula sized to accept a Mammotome®, Tru-Cut®, orSenoCor® biopsy device. Typically, plug 16 and markers 17 and 18 willhave diameters determined by the size of a bore 15 and typically will beabout 0.02 inch (0.5 mm) to about 0.5 inch (12 mm), preferably about0.04 inch (1 mm) to about 0.3 inch (8 mm). Plug 16 may have slightlylarger transverse dimensions to provide a tight fit. In addition, plugs16 and 20 and short term markers 17 will have a length of about 0.04inch (1 mm) to about 0.8 inch (20 mm), preferably about 0.1 inch (2.5mm) to about 0.6 inch (15 mm).

[0045] The fibrous markers 18 and 19 are preferably rolled or foldedpieces of fibrous material such as oxidized cellulose or oxidized,regenerated cellulose which has been compressed and impregnated with abinding agent such as polyethylene glycol and freeze dried in thecompressed condition. The fibrous material may be rolled up by itself,as shown in FIG. 5, or wrapped about a matt-like core 30 as shown inFIG. 4. The fibrous marker is generally configured to be slidablydisposed within the inner lumen of the delivery cannula 11, and beforedelivery is about 0.5 mm to about 12 mm, preferably about 1 to about 8mm in diameter and about 5 to about 30 mm, preferably about 10 to about25 mm in length. Upon contact with a body fluid or other water basedfluid, the length of the fibrous marker remains about the same but thewrapped structure unfolds upon swelling to a width of about 5 to about25 mm, usually about 10 to about 20 mm. With a radiopaque marker elementclamped about a center portion of the wrapped fibrous marker, thefibrous marker expands into a generally bow-tie shape when exposed tobody fluids. However, even though secured to the fibrous marker, theradiopaque marker element need not restrict the expansion of the fibrousmarker.

[0046] The manufacture and use of fibrous marker 18 with a core 30 isschematically illustrated in FIGS. 4A-4F. A felt pad or mat 31 ofoxidized, regenerated cellulose about 0.125 to about 0.375 inch (3.2-9.3mm), preferably about 0.25 inch (6.4 mm) thick is impregnated with a 10%(Wt.) polyethylene glycol in a 70% isopropyl alcohol solution and thencompressed to a mat about 0.03 to about 0.05 inch (0.76-1.3 mm) thick. Areduction in thickness of 80% or more is suitable. The compressed mat 31is cut up into elongated strips 32 with square or near square transversecross-sectional shapes which form the core 30. The core 30 is wrapped ina fabric 33 of oxidized regenerated cellulose about 5 to about 10 mm inwidth and about 20 mm in length, compressed and impregnated with the 10%PEG dispersion and then freeze dried to a diameter of about 0.065 inch(1.65 mm). Elevated temperatures may be employed to dry the material.The fabric 33 should make at least one, preferably two or more completewraps about the core 30. The wrapped and compressed product may then becut to a desired length to form the fibrous marker 18. Alternatively,the uncompressed mat 31, the strip 32 and fiber wrap 33 may be providedat the desired length for the fibrous marker 18, wrapped and thencompressed. A radiographically detectable marker element 34 may beformed of a radiopaque wire about 0.005 to about 0.01 inch, (0.13-0.25mm) may then be crimped about or embedded in a central portion (or otherdesired portion) of the marker 13. The fibrous marker 18 is then readyfor deployment. As shown in FIG. 1A, only fibrous marker 18 is providedwith marker element 34. Marker 19 may be formed in the same or similarmanner but without the radiopaque element 34.

[0047] Fibrous markers without the core member 30 may be formed byrolling or folding into the desired configuration. The fibrous material,oxidized rayon felt is first impregnated with a 10% PEG dispersion,compressed and then freeze dried. The dried felt material is rolledagain compressed in the rolled state, impregnated with a 10-30% PEGsolution, and freeze dried in the rolled compressed condition. The rayonfelt material can be initially oxidized by treating in a solution of 80%(by vol.) Nitric Acid, 20% (by vol.) Sulfuric Acid and 1% (by weight)Sodium Nitrite. The felt is treated in the oxidizing, acidic solution atroom temperature for about 4.5 hours and then rinsed with deionizedwater.

[0048] Radiopaque elements 28 and 34 may be made with suitableradiopaque material, including stainless steel, platinum, gold, iridium,titanium, tantalum, tungsten, silver, rhodium, nickel, bismuth, otherradiopaque metals, alloys and oxides of these metals, barium salts,iodine salts, iodinated materials, and combinations of these. Theradiopaque elements 28 and 34 may also be configured for detection byMRI. Radiopaque materials and markers may be permanent, or may betemporary and not detectable after a period of time subsequent to theirplacement within a patient. Colorants, such as dyes (e.g., methyleneblue and carbon black) and pigments (e.g., barium sulfate), may also beincluded in markers 17 and 18 and plugs 16 and 19 embodying features ofthe invention.

[0049]FIG. 5 schematically illustrates the use of a marker deliverysystem 10 to deliver markers to a desired location 35 within a patient'sbody. The desired location 35 is typically a cavity from which a biopsysample has been, or is to be, taken, or a lesion that has been or willbe removed or otherwise treated. In FIG. 4, the marker delivery system10 is shown inserted into a breast 40 through a guide cannula 41 untilthe distal end 24 is disposed at the delivery site, cavity 35 where atissue specimen has been removed. While an operator holds the system 10by the handle 15 of the delivery tube 11, the plunger 20 is pressedfurther into the bore 12 of delivery cannula 11 to discharge thereleasable plug 16 and markers 17 and 18 into the cavity 35. FIG. 6schematically illustrates the plug 16 and markers 17, 18 and 19 withinthe cavity 35 after deployment. When the markers contact body fluidwithin the cavity 35, they tend to swell and thereby further fill thecavity. The fibrous markers 18 and 19 generally block the accessingtrack 36 to the cavity 35 so that none of the smaller markers 17 will belost through the track 36. Marks 37 are provided on the proximal end ofcannula 11 to provide end location information to the operator.

[0050]FIG. 7 illustrates the distal portion 50 of cannula 51 of analternative delivery system that is essentially the same as that shownin FIGS. 1A-1C except that the distal tip 52 of cannula 51 is configuredin a needle-like shape. The delivery system cannula 51 may be used inconjunction with a guide cannula (not shown) or the cannula 51 can beinserted directly through tissue to reach the target site without theneed for a guide cannula. The releasable plug 53 is secured in thedischarge opening 54 as in the previously discussed embodiment. Theexposed face 55 of the plug 53 is preferably flush with the dischargeopening 54 of the distal tip 52.

[0051] Insertion of marker delivery devices embodying features of theinvention may be performed with or without the aid of an imaging device,such as an ultrasound imaging device, an X-ray imaging device, a MRIdevice, or other imaging device. Alternatively, or additionally,insertion may be visually guided, or may be guided by palpation or byother means.

[0052] The size and composition of the short term markers 17 areselected so as to remain in place within the patient and be detectableby ultrasound for at least 2 weeks, preferably at least 6 weeks to havepractical clinical value. However, the short term markers should not bedetectable by ultrasound after about one year, preferably not afterabout six months, so as to avoid interfering with subsequent siteexamination. For most clinical purposes, a suitable in-situ lifespanwhen the short term marker is ultrasonically detectable is about six toabout twenty weeks. The radiopaque and MRI detectable marker elementsgenerally will have much longer lifespans.

[0053]FIG. 8 illustrates the distal shaft section 60 of an alternativedelivery cannula 61 which has a fibrous releasable plug 62 in the innerlumen 63 of the distal shaft section which at least partially occludesthe discharge opening 64 in the distal end of the shaft. The fibrousreleasable plug 62 may be formed as shown in FIGS. 2, 3 and 4A-F.

[0054] The inner lumen proximal to the fibrous releasable plug 62 isfilled with a particulate marker material 65. The corresponding parts ofthe system are the same as that shown in FIGS. 1A-1C. Plunger 66 isslidably disposed within the inner lumen 63 to eject the powdered mass65. The particulate marker material 65 may be discharged dry or mixedwith a suitable fluid and discharged as a slurry.

[0055] The particulate may be formed of a biocompatible andbio-resorbable polymeric material such as polylactic acid, polyglycolicacid, polycaprolactones, poly(esters), poly(hydroxy acids),poly(lactones), poly(amides), poly(ester-amides), poly(amino acids),poly(anhydrides), poly(ortho-esters), poly(carbonates),poly(phosphazines), poly(thioesters), poly(urethanes), poly(esterurethanes), polysaccharides, polybutyric acid, polyvaleric acid, andcopolymers, polymer alloys, polymer mixtures, and combinations thereof.Of those, polylactic acid, polyglycolic acid, and polycaproic acid arepreferred. The polymeric material in particulate form should havecavities or entrap bubbles which facilitate remote detection.

[0056] Suitable particulate materials have particle sizes typicallyabout 20 microns to about 2000 microns, preferably about 20 microns toabout 800 microns and more preferably about 300 microns to about 500microns. The particulate should have cavities for USI with maximumdimensions of about 10 microns to about 500 microns, preferably about 20microns to about 200 microns. The polymeric particulate materialssuitable for use in making ultrasound-detectable biopsy marker materialstypically have a bulk density of about 0.8 g/ml to about 1.5 g/ml,preferably about 0.8 g/ml to about 1 g/ml. The particulate may alsocontain or be mixed with binding agents such as polyethylene glycol,polyvinyl alcohol and the like. Polysaccharide particulate or powder maybe incorporated into the particulate mass in amounts up to about 50% (byweight) of the total particulate mass for purposes of hemostasis.

[0057] While particular forms of the invention have been illustrated anddescribed herein in the context of a breast biopsy site, it will beapparent that the device and methods having features of the inventionmay find use in a variety of locations and in a variety of applications,in addition to the human breast. Moreover, various modifications can bemade without departing from the spirit and scope of the invention.Accordingly, it is not intended that the invention be limited to thespecific embodiments illustrated. It is therefore intended that thisinvention to be defined by the scope of the appended claims as broadlyas the prior art will permit, and in view of the specification if needbe. Moreover, those skilled in the art will recognize that featuresshown in one embodiment may be utilized in other embodiments. Terms suchas “element”, “member”, “device”, “section”, “portion”, “step”, “means”and words of similar import when used in the following claims shall notbe construed as invoking the provisions of 35 U.S.C. §112(6) unless thefollowing claims expressly use the terms “means” followed by aparticular function without specific structure or “step” followed by aparticular function without specific action. All patents and patentapplications referred to above are hereby incorporated by reference intheir entirety.

What is claimed is:
 1. A marker delivery device for an intracorporealtissue site, comprising: a) an elongated delivery cannula which has adistal end, an inner lumen and a discharge opening in the distal end incommunication with the inner lumen; b) at least one remotely detectablemarker mass which is disposed within the inner lumen of the deliverycannula; and c) a releasable plug which has a remotely detectableelement incorporated therein and which is disposed at least in partwithin a distal portion of the inner lumen distal to the remotelydetectable marker mass so as to occlude the discharge opening in thedistal end.
 2. The marker delivery device of claim 1 wherein thereleasable plug is formed at least in part of oxidized cellulose.
 3. Themarker delivery device of claim 1 wherein the releasable plug is formedat least in part of a material which expands in the presence of bodyfluids.
 4. The marker delivery device of claim 1 wherein the releasableplug is formed at least in part of polyethylene glycol.
 5. The markerdelivery device of claim 4 wherein the polyethylene glycol of which thereleasable plug is at least partially formed has a molecular weight ofabout 5000 to about 120,000 Daltons.
 6. The marker delivery device ofclaim 4 wherein the polyethylene glycol of which the releasable plug isat least partially formed has a molecular weight of about 5000 to about20,000 Daltons.
 7. The marker delivery device of claim 4 wherein thepolyethylene glycol of which the releasable plug is at least partiallyformed has a molecular weight of about 8000 to about 10,000 Daltons. 8.The marker delivery device of claim 1 wherein the releasable plug has anon-magnetic marker element which is remotely detectable by magneticresonance.
 9. The marker delivery device of claim 1 wherein the markerelement is formed of a material selected from the group consisting oftitanium, platinum, gold, iridium, tantalum, tungsten, silver, rhodium.10. The marker delivery device of claim 1 wherein the at least oneremotely detectable marker body is formed at least in part of fibrousmaterial.
 11. The marker delivery device of claim 10 wherein the atleast one fibrous marker body has a radiographic detectable element 12.The marker delivery device of claim 10 wherein the at least one fibrousmarker body is formed at least in part of a bioabsorbable fibrousmaterial.
 13. The marker delivery device of claim 10 wherein the atleast one fibrous marker body is formed of oxidized cellulose.
 14. Themarker delivery device of claim 10 wherein at least one fibrous markerbody is formed of oxidized regenerated cellulose.
 15. The markerdelivery device of claim 11 wherein the radiographically detectableelement surrounds an exterior portion of the fibrous marker body. 16.The marker delivery device of claim 1 wherein at least one remotelydetectable marker mass is formed of polymeric material selected from thegroup consisting of polylactic acids, polyglycolic acids, copolymers andblends thereof and is disposed in the inner lumen proximal to thereleasable plug.
 17. The marker delivery device of claim 15 wherein atleast one remotely detectable fibrous marker body formed at least inpart of bioabsorbable fibrous material selected from the groupconsisting of oxidized cellulose and oxidized regenerated cellulose isdisposed proximal to the remotely detectable marker bodies formed ofpolymeric material.
 18. The marker delivery device of claim 1 whereinthe releasable plug tip is formed at least in part of fibrous material.19. The marker delivery device of claim 18 wherein the fibrousreleasable plug tip has a radiographic detectable element.
 20. Themarker delivery device of claim 18 wherein the releasable plug tip isformed at least in part of a bioabsorbable fibrous material.
 21. Themarker delivery device of claim 18 wherein the fibrous releasable plugtip is formed of oxidized cellulose.
 22. The marker delivery device ofclaim 18 wherein the fibrous releasable plug tip is formed of oxidizedregenerated cellulose.
 23. The marker delivery device of claim 19wherein the radiographically detectable element surrounds an exteriorportion of the fibrous releasable plug tip.
 24. The marker deliverydevice of claim 18 wherein at least one remotely detectable marker massis formed of polymeric material selected from the group consisting ofpolylactic acids, polyglycolic acids, copolymers and blends thereof andis disposed in the inner lumen proximal to the fibrous releasable plug.25. The marker delivery device of claim 21 wherein the fibrousreleasable plug tip is formed at least in part of bioabsorbable fibrousmaterial selected from the group consisting of oxidized cellulose andoxidized regenerated cellulose is disposed proximal to the remotelydetectable marker bodies formed of polymeric material.
 26. The markerdelivery device of claim 1 including a plunger which is slidablydisposed within the inner lumen of the cannula and which has a distalend proximal to marker bodies in the inner lumen.
 27. A marker deliverydevice for an intracorporeal tissue site, comprising: a) an elongateddelivery cannula which has a distal end, a discharge opening in thedistal end and an inner lumen extending to and in communication with thedischarge opening; and b) a releasable plug which has an MRI detectablemarker element incorporated therein and which is disposed at least inpart within a distal portion of the inner lumen so as to occlude thedischarge opening in the distal end.
 28. The marker delivery device ofclaim 27 wherein the releasable plug is formed at least in part of amaterial selected from the group consisting of oxidized cellulose oroxidized regenerated cellulose.
 29. The marker delivery device of claim27 wherein the releasable plug is formed at least in part of a materialwhich expands in the presence of body fluids.
 30. The marker deliverydevice of claim 29 wherein the releasable plug is formed at least inpart of polyethylene glycol.
 31. The marker delivery device of claim 27wherein at least one remotely detectable marker body is slidablydisposed within the inner lumen of the delivery cannula proximal to thereleasable plug.
 32. The marker delivery device of claim 31 wherein theat least one remotely detectable marker body disposed proximal to thereleasable plug is formed at least in part of fibrous material.
 33. Themarker delivery device of claim 32 wherein the fibrous marker body isexpandable upon contact with body fluid or other water based fluid. 34.The marker delivery device of claim 32 wherein the fibrous material isbioabsorbable.
 35. The marker delivery device of claim 34 wherein thefibrous material is oxidized cellulose.
 36. The marker delivery deviceof claim 34 wherein the fibrous material is oxidized regeneratedcellulose.
 37. The marker delivery device of claim 32 wherein the atleast one marker body formed of fibrous material has a radiographicimageable element.
 38. The marker delivery device of claim 37 whereinthe radiographically detectable element surrounds a portion of thefibrous marker body.
 39. The marker delivery device of claim 27 whereina plunger is slidably disposed within the inner lumen of the cannulawith a pusher end proximal to the marker bodies in the inner lumen. 40.The marker delivery device of claim 27 wherein the MRI detectable markerelement is about 0.5 to about 5 mm in maximum dimension.
 41. The markerdelivery device of claim 27 wherein the MRI detectable marker element isabout 1 to about 3 mm in maximum dimension.
 42. A marker delivery devicesystem for an intracorporeal site within a patient, comprising: a. anelongated delivery cannula which has a distal end, a discharge openingin the distal end and an inner lumen extending to and in communicationwith the discharge opening; b. a releasable plug disposed within theinner lumen so as to at least partially occlude the discharge opening;and c. at least one remotely detectable, short term marker disposedwithin the inner bore proximal to the releasable plug; and d. at leastone fibrous marker disposed within the inner lumen proximal to the atleast one short term marker.
 43. The marker delivery device of claim 42wherein the releasable plug is formed at least in part of a materialwhich expands in the presence of body fluids.
 44. The marker deliverydevice of claim 42 wherein the releasable plug is formed at least inpart of polyethylene glycol.
 45. The marker delivery device of claim 42wherein the releasable plug is covered with polyethylene glycol.
 46. Themarker delivery device of claim 42 wherein at least one remotelydetectable marker body is slidably disposed within the inner lumen ofthe delivery cannula distal to the releasable plug.
 47. The markerdelivery device of claim 42 wherein the at least one remotely detectablemarker body disposed distal to the releasable plug is formed at least inpart of fibrous material.
 48. The marker delivery device of claim 47wherein the fibrous material is bioabsorbable.
 49. The marker deliverydevice of claim 46 wherein the fibrous material is oxidized cellulose.50. The marker delivery device of claim 46 wherein the fibrous materialis oxidized regenerated cellulose.
 51. The marker delivery device ofclaim 46 wherein the at least one marker body formed of fibrous materialhas a radiographic imageable element
 52. The marker delivery device ofclaim 51 wherein the radiographically detectable element surrounds aportion of the fibrous marker body.
 53. The marker delivery device ofclaim 42 wherein a plunger is slidably disposed within the inner lumenof the cannula with a pusher end proximal to the marker bodies in theinner lumen.
 54. The marker delivery device of claim 42 wherein thereleasable plug has a non-magnetic, MRI detectable marker elementincorporated therein.
 55. The marker delivery device of claim 54 whereinthe non-magnetic, MRI detectable marker element is formed of a materialselected from the group consisting of titanium, platinum, gold, iridium,tantalum, tungsten, silver and rhodium.
 56. The marker delivery deviceof claim 54 wherein the non-magnetic, MRI detectable marker element isabout 0.5 to about 5 mm in maximum dimension.
 57. The marker deliverydevice of claim 54 wherein the non-magnetic, MRI detectable markerelement is about 1 to about 3 mm in maximum dimension.
 58. A markerdelivery device for an intracorporeal tissue site, comprising: a) anelongated delivery cannula which has a distal end, an inner lumen and adischarge opening in the distal end in communication with the innerlumen; b) at least one remotely detectable marker mass which is formedat least in part of particulate and which is disposed within the innerlumen of the delivery cannula; and c) a releasable plug which has aremotely detectable element incorporated therein and which is disposedat least in part within a distal portion of the inner lumen distal tothe remotely detectable marker mass so as to occlude the dischargeopening in the distal end.
 59. The marker delivery device of claim 58wherein the marker mass is remotely detectable by ultrasound.
 60. Themarker delivery device of claim 58 wherein the particulate of the markermass is formed of bio-resorbable material.
 61. The marker deliverydevice of claim 58 wherein the particulate has a particle size of about20 to about 2000 microns.
 62. The marker delivery device of claim 58wherein the particulate has a particle size of about 100 microns toabout 1500 microns.
 63. The marker delivery device of claim 58 whereinthe particulate has a particle size of about 500 microns to about 900microns.
 64. The marker delivery device of claim 58 wherein theparticulate has bubble cavities.
 65. The marker delivery device of claim64 wherein the bubble cavities of the particulate is about 10 microns toabout 500 microns in maximum dimension.
 66. The marker delivery deviceof claim 64 wherein the bubble cavities of the particulate are about 50microns to about 200 microns.
 67. The marker delivery device of claim 60wherein the particulate is formed at least in part of bio-resorbablepolymeric material selected from the group consisting of poly(esters),poly(hydroxy acids), poly(lactones), poly(amides), poly(ester-amides),poly(amino acids), poly(anhydrides), poly(ortho-esters),poly(carbonates), poly(phosphazines), poly(thioesters), poly(urethanes),poly(ester urethanes), polysaccharides, polylactic acids, polyglycolicacids, polycaproic acids, polybutyric acids, polyvaleric acids, andcopolymers, polymer alloys, polymer mixtures, and combinations thereof.68. The marker delivery device of claim 60 wherein the particulate isformed at least in part of bio-resorbable polymeric material selectedfrom the group consisting of polylactic acids, polyglycolic acids,polycaproic acids, and copolymers, polymer alloys, polymer mixtures, andcombinations thereof.
 69. The marker delivery device of claim 52 whereinthe bio-resorbable material comprises about 65% by weight polylacticacid and about 35% by weight polyglycolic acid.
 70. Theultrasound-detectable biopsy marker mass of claim 58, wherein saidbio-resorbable polymeric material comprises a polymeric material havingan average molecular weight of less than about 60 kD selected from thegroup consisting of polylactic acid and polycaproic acid polymers,copolymers, polymer alloys, polymer mixtures, and combinations thereof.71. The marker delivery device of claim 60 wherein the particulate has abulk density of about 0.8 g/ml to about 1.1 g/ml.
 72. The markerdelivery device of claim 60 wherein the particulate is held together bya binding agent.
 73. The marker delivery device of claim 72 wherein thebinding agent is selected from the group consisting of gelatin,polyethylene glycol, polyvinyl alcohol, glycerin, acrylic hydrogels,organic hydrogels, polysaccharides and combinations thereof.
 74. Themarker delivery device of claim 60 wherein the marker mass comprisesgelatin and bio-resorbable polymeric particulate material having bubblecavities.
 75. The marker delivery device of claim 74 wherein the gelatinbinding agent is selected from the group consisting of bovine collagen,porcine collagen, ovine collagen, equine collagen, synthetic collagen,agar, synthetic gelatin, and combinations thereof.
 76. An intracorporealmarker comprising an expandable bioabsorbable fibrous body with aradiopaque marker element secured to the fibrous body.
 77. Theintracorporeal marker of claim 76 wherein the radiopaque marker elementis incorporated into the fibrous body.
 78. The intracorporeal marker ofclaim 76 wherein the radiopaque marker is disposed about the fibrousbody.
 79. The intracorporeal marker of claim 76 wherein the radiopaquemarker is incorporated into the fibrous body.
 80. The intracorporealmarker of claim 76 wherein the fibrous body is formed at least in partof a bioabsorbable material selected from the group consisting ofoxidized cellulose, oxidized regenerated cellulose, polylactic acid, acopolymer of polylactic acid and glycolic acid, and polycaprolactone.81. The intracorporeal marker of claim 80 wherein the cellulose isoxidized, regenerated cellulose.
 82. The intracorporeal marker of claim76 wherein the fibrous body is formed of material which swells in thepresence of body fluids or other water based fluids.
 83. Theintracorporeal marker of claim 76 wherein the fibrous body is formed atleast in part of woven fabric.
 84. The intracorporeal marker of claim 76wherein the fibrous body is formed at least in part of felt fabric. 85.The intracorporeal marker of claim 76 wherein the fibrous body iscompressed.
 86. The intracorporeal marker of claim 85 wherein thecompressed fibrous body has incorporated therein a binding agent to holdthe fibrous body in the compressed condition.
 87. The intracorporealmarker of claim 86 wherein the binding agent is selected from the groupconsisting of water soluble polymers selected from the group consistingof polyvinyl alcohol, polyethylene glycol and polyvinyl pyrollidone. 88.The intracorporeal marker of claim 76 wherein the fibrous body includesat least one bioactive component selected from the group consisting oftherapeutic and diagnostic agents incorporated therein.
 89. Theintracorporeal expandable marker of claim 88 wherein the incorporatedtherapeutic or diagnostic agent is selected from the group consisting ofa hemostatic agent, an anesthetic agent, a coloring agent, an antibioticagent, an antifungal agent, an antiviral agent, a chemotherapeutic agentand a radioactive agent.
 90. The intracorporeal expandable marker ofclaim 78 wherein the fibrous body contains a bioabsorbable materialselected from the group consisting of polylactic acid, a co-polymer ofpolylactic acid and glycolic acid, polycaprolactone, collagen andmixtures thereof, including mixtures with the oxidized cellulose. 91.The intracorporeal expandable marker of claim 78 wherein the fibrousbody includes a binding agent.
 92. The intracorporeal expandable markerof claim 76 wherein the radiographically detectable marker element isdisposed at a central portion of the fibrous body.
 93. Theintracorporeal expandable marker of claim 76 wherein a constrictingmember holds a portion of the fibrous body to prevent its expansion. 94.The intracorporeal expandable marker of claim 93 wherein theconstricting member holds a central portion of the fibrous body toprevent its expansion.
 95. The intracorporeal expandable marker of claim76 wherein the radiographically detectable marker element is aconstricting member which holds a portion of the fibrous body to preventits expansion.
 96. The intracorporeal expandable marker of claim 95wherein the radiographically detectable constricting member holds acentral portion of the fibrous body to prevent its expansion.
 97. Theintracorporeal expandable marker of claim 96 wherein the constrictedfibrous body is configured to expand into a bow-tie shape when exposedto body fluid or other water based fluid.
 98. The intracorporealexpandable marker of claim 76 wherein the fibrous body has a core formedof bioabsorbable felt surrounded by a bioabsorbable fabric jacket. 99.The intracorporeal expandable marker of claim 95 wherein theradiographically detectable marker element is a radiopaque wire elementclamped about a central exterior portion of the fibrous body.
 100. Theexpandable intracorporeal marker of claim 95 wherein the fibrous masshas been compressed at least 25%.
 101. An intracorporeal markercomprising a compressed expandable bioabsorbable fibrous body which hasbeen compressed and bound in the compressed condition.
 102. Theintracorporeal marker of claim 101 wherein the fibrous body is bound bya binding agent selected from the group consisting of water solublepolymers selected from the group consisting of polyvinyl alcohol,polyethylene glycol and polyvinyl pyrollidone.
 103. The intracorporealmarker of claim 101 wherein the fibrous body is about 0.5 mm to about 12mm in diameter.
 104. The intracorporeal marker of claim 101 wherein thefibrous body is, about 1 to about 8 mm in diameter.
 105. Theintracorporeal marker of claim 101 wherein the fibrous body is about 5to about 30 mm in length.
 106. The intracorporeal marker of claim 101wherein the fibrous body is about 10 to about 25 mm in length.